Method of manufacturing reinforced tubular or hollow bodies.



L. H.- REN'TZSCH.

' METHOD OBMANUFAGTURING REINFORCED TUBULAR 0R HOLLOW BODIES.

APPLIOATION FILED my '1. 1907.

937,173, I Patented Oct-1945109.

2 sigma-sum 1.

L. H. RBNTZSOH. METHOD or MANUFACTURING REINFORCED TUBULAR on HOLLOWBODIES.

. APPLIOATION FILED HAY '7. 1907. 937, 1 7 8;

2 BHEBTB-8HBET 2.

; l L. 'I J Patented 0ct.19','1909.

LOUIS HERMANN RENTZSCH, OF MEISSEN, GERMANY.

METHOD MANUFACTURING REINFORCED TUBULAR OR HOLLOW" BODIES Specificationof Letters Patent. Patented Oct. 19', 1909.

Application filed May 7, 1907. Serial No. 372,318.

To all whom it may concern:

Be ..1t known that .l, Louis llmeuaxx lti m'rzscn, a subject of the Kingof Saxony,

residing at Meissen, in Saxony, Empire of Germany, have invented acertain new and useful Method of illanufacturing Reinforced Tubular orHollow Bodies, of which the following is a specification.

This invention relates to the, centrifugal manufacture of hollow ortubular bodies of plastic material (more particularly cement, and gypsumwith addltion of organic or inorganic fibrous materials) provided withan insertion of so-called expanded metal,

whereby the bodies, owing to the peculiar property of the insertion,"become exceedingly strong and rigid.

The invention further consists in improv ments in the .centrifugalmanufacture of such hollowflbodies, the'object'of which is to effect acomplete embedding of the expanded metal insertion in the wall produced.

The present invention relates to improvements in the manufacture ofreinforced cement and like tubes or other hollow bodies formed by thecentrifugal application of the cement material to an insertion ofexpended metal in such a manner that an cxceedingly strong and rigidstructure is at tamed, and the olnect. of the invention is to -50 ar'ange the expanded metal inscrtion'that a complete embedding of the samein the cement material is obtained.

In the accon'i 'ianymg drau u gsl lgure 1 1s a diagrammatic view showingthe mold,

and theexpanded metal therein, and the di rcction inwhich the deposit ofthe plastic material takes place.' hoth when the mold is rotated in thedirection of the arrows f and a. Fig. 2 isa cross-section of the moldwith a portion of the expanded metal therein, the metal being arrangedin a direction opposite to that in Fig. 1, but properly for the rotationof the mold in the direction of the arrow. F 3 is an'elcvation partly insection of the complete reinforced tube with a portion broken away.

simila'r letters of reference in the seve a1 figures indicate the sameparts.

In carrying out the present invention it is necessary that the expandedmetalshould be properly inserted or arranged in the mold. First of all,the expanded'metal must be made into tubular or hollow shape in suchmanner thatthe longitudinal direction of its meshes which,-as is we llknown, are situated at a right angle to the direction of erpansiomshould be in the lmigitmlimil direction of the tube, Fig. 3, as expandedmetallms the greatest bending and tensional strength in that direction.In the tube mold the bridges of the expanded metal, are, not arrangedhowever with their width.iuradial direction relatively tothe axis ofthettubc. but in a position which forms an augle of about 30 with theradius of the tubular body. I p p H i The directionof rotation of thetube mold provided with the expanded metal-insertion is of the greatestuuportauce as 'Ill be shown by'the following considerations.

Referring particularly to Fig. 1 of the drawings. the letter indicates aciiiular surface which corresponds to tllt r() 'S-St tion of the mold.Let us assume thatithis circular surface is rotated about its center Bin the direction of the arrow a and tliat'a particle of the mass isarranged at Icon the circularsurface. The particle is assui'ncd to befreely movable on the circularsurface. During the rotation. thisparticle will have the tendency to rotate with the same angular velocityabout the center 13. as the circular surface itself. .\s.'howcrcr,.theparticle is not rigidly connected to the circular surface which isbeing' rotated. its speed 'ofrotation will he reduced by the iui'luenccof itsfown weight (inertia) and by friclimi'=(resistancc of air),compared to the spccdof rotation of the corre:-poml|ug points of thecircular surt';=cc. l't', therefore. the surface rotates in a move to c.

certain time in such manner that apoint on 3', the particle I) will notmove. to I)", but only to I)". At the same time, however, centrifugalforce acts on the particle and has the tend cue to throw the particleout of its circular path outward in the direction of the arrow 1:. Fromthe combined action of the said reduc tion of speed and of centrifugalforce, it will be found that the particle will in reality It willdescribe relatively to the circular surface a path represented by thecurve d. As the speed of rotation of the single points of the circularsurface increases with the length of the radius, the curve will deviatemore and more strongly from the direction of rotation of the surface itmoves toward the circumference.

Ifet the circumference of the surface there is a bridge e of expandedmetal, which forms with ,the corresponding radius of the cirthe wideside of each bridge, which is sit-.

cular surface an angle of about 30, and which races toward the axis ofthe tube, with the side which is in front in the direction of rotation,the particle-of the mass will strike the said side at an angle of aabout (30.

There will thus be produced behind the bridge an area 2' into which theparticle of the mass cannot penetrate whichever be the point from whichits movement starts. If

on the contrary, thedirection of rotation of the surface is reversed,that is to say, if it is rotated in the direction of the chain-dottedarrow 7, a particle of the mass situated at 9 will describe thechain-dotted curve lvrelatively to the surface. If the position of thebridge remains the same, the particle of the mass can reach any point ofthe circumference on the circular surface, as its line of advance is inthe plane of the bridge itself. The bridge will therefore, no longerproduce a protected zone into which the material cannot penetrate- Theseconditions are of importance in making reinforced hollow structurescentrifugally. If the direction of rotation is selected in such mannerthat the Wide sides of the bridges (in contradistinction to their edges)of. the ex-" panded metal inserted; facing the axis of the tube, aresituated facing or opposite the direction ofrotation, the bridge itselfwould form'throughoutthe width a sheltered pressure-free zone behinduated'at the back-relatively to the direction of rotation. This zonecould ,then be filled with the mass only by Sid pressure and moreover,the mass would be thrown by centrifugal force away from these widesides' of the bridges facing the .wall of the mold. When the expandedmetal is in such position relatively to the, direction of rotation,hollow spaces. are formed in the wall of the tube, filled'with air or:water, which give rise to blow holes and cracks and to loose. and leakyportions in the mass. 'If, howtheinarrow sides or edges of whole of itslength and i .to secure by Letters Patent 15:-

. the rear sides ever, the direction of rotation of the tubular mold isselected in "such manner thztii'the wide sides of the bridges, facingthe tubular axis, are situated at the rear relatively to the directionof rotation, the plastic mass will be projected in the direction of theplane of the bridges and will therefore only strike the bridges.resulting force, which effects the pro ection of the mass, can 'in thatcase, freely act in the whole area of the mesh formed by the bridges andwill press the whole mass therein contained into the mesh in a uniformand strong manner. In this case, therefore, the throwing off of the massfrom the Wide side of the bridges facing outward will not take place.The formation of air and water' The blow holes and other loose .anddefective places in the mass casing 'is thus'avoided and the thoroughconnection of the expanded metal with the mass into one single body isinsured. The expanded metal frame work -must he; therefore, always arraned in the centrifugal mold, as shown in ig. 2, as above describedrelatively to the direction of rotation which is represented by thearrow in said figure.

The advantages given by the ex anded metal insertion to the finished worproduced by centrifugal force cannot be obtained by other metalinsertions of the same strength, lightness and cheapness.

\Vhat I claim as my invention and desire A method of manufacturingtubular or hollow bodies from plastic material with expanded metalinsertion consisting in inserting the eXpanded metal into a centrifu almold in such manner that the sides of itsv bridges toward the axis ofthe mold form relatively to the direction of rotation substantially asset forth.

In-testimony whereof I havesigned my name to this specification in thepresence of two subscribin witnesses. v

LOUIS IERMANN RENTZSCH. Witnesses: \Vnnami PAUL Taruanoan, RICHARDFRIEDRICH Juries Irran'rn.

